Compact cameras are widely used today. And, to make these compact cameras more handy to carry, much smaller ones are desired. In various attempts to realize the further miniaturization of these compact cameras, it is essential to reduce the space to house a photographic film.
When loaded in a compact camera, a photographic film is generally wound on a spool in roll. Therefore, to reduce the housing space for a photographic film without decreasing the number of exposures, the film itself must be made thinner. The thickness of a photographic support now in use is about 120 to 125 .mu.m and considerably greater than that of a light-sensitive layer (20 to 30 .mu.m) formed on the support. Accordingly, thinning a photographic support is the most effective means for reducing the thickness of a whole photographic film.
As photographic supports used now, triacetylcellulose (occasionally abbreviated as TAC) films are the most typical. However, TAC films are poor in mechanical strength by nature; therefore, when made much thinner, TAC films become apt to cause problems during conveyance or handling in a camera or in the developing process after photographing. Accordingly, it is not expedient to make the thickness of a TAC film support less than the thickness of a photographic support in use today.
On the other hand, polyethylene terephthalate films, which have so far been employed as films for X-ray photography or for photomechanical process in the photographic industry, are excellent in mechanical strength and, thereby, come to attract much attention as a photographic support which may enable the reduction of the thickness of a photographic film without lowering the mechanical strength.
Especially, the technique to provide a polyester resin with hydrophilicity disclosed in Japanese Pat. O.P.I. Pub. Nos. 120857/1990, 244446/1989, etc. has made possible to prevent polyester resin films from curl. Since then, active studies have been made with the aim of developing a thinner photographic film by use of a polyester resin support.
When such a polyester resin photographic support is used, a thinner photographic film can be certainly obtained; but, there arises a problem that the photographic film becomes apt to curl because of high expansion property, caused by moisture absorption an emulsion layer formed on one side of a support. To maintain a curling balance of a photographic film, there is a method of using gelatin in a backing layer formed on the side of the support opposite to the emulsion layer.
However, when gelatin was used in the backing layer and a cine automatic processor was used for processing, stain due to roll marks were generated on the backing layer, and it was found that serious problems due to excessive stain markedly deteriorated image quality of a print.
When the amount of gelatin used for the backing layer is reduced in order to solve this problem, the stain due to roll marks on the backing layer tend not to occur. In this method, however, curling balance of the film becomes insufficient, causing serious curling on the side of the emulsion layer. Due to this, scratches are easily made on the backing layer by a printer or the like. In addition, in printing, because curling has not been removed even after development. In addition, this curling causes a critical problem such as, out-of-focus or remarkable deterioration of image quality of prints are caused.